TUESDAY, Feb. 3, 2015 (HealthDay News) -- A healthy diet low in red meat and rich in whole grains might reduce the risk of developing the crippling chronic lung disease known as COPD, new research suggests.

Researchers tracked more than 120,000 men and women and found healthy eaters were one-third less likely to develop COPD compared to big consumers of red meat, refined grains, sugary drinks and alcohol.

"The predominant risk factor for COPD in the developed world is cigarette smoking," said study lead author Raphaelle Varraso, a researcher with the unit of aging and chronic diseases at the National Institute of Health and Medical Research in Villejuif, France.

"But up to one-third of COPD patients have never smoked, suggesting that other factors are involved," Varraso said. "This novel finding supports the importance of diet in COPD [development]."

The study was published online Feb. 3 in the BMJ.

The finding builds on a wide body of prior research suggesting that a healthy diet lowers the risk for heart disease and cancer. And good eating habits seem to lower COPD risk for both smokers and nonsmokers alike, the researchers found.

COPD, or chronic obstructive pulmonary disease, is an umbrella term for several chronic lung diseases, including emphysema and bronchitis, that lead to blocked air passages and restricted oxygen flow. Routine breathing can be difficult and painful for someone with COPD -- the third leading cause of death in America, according to the American Lung Association.

To explore the impact of diet on COPD risk, the investigators focused on the health and eating habits of more than 73,000 women who participated in the U.S. Nurses' Health Study between 1984 and 2000. They also looked at the nutrition profiles of over 47,000 men enrolled in the Health Professionals Follow-Up Study between 1986 and 1998.

Most of the participants were white, and all worked as health professionals.

By the end of each study's time frame, 723 women and 167 men developed COPD. The subsequent analysis indicated that COPD risk was far lower among those whose diets were light on red meat, sweetened drinks and alcohol, and rich in vegetables, complex carbohydrates such as green vegetables and whole grains, and polyunsaturated fats and nuts.

Polyunsaturated fats include soybean, safflower, corn and canola oils, and fish such as salmon, trout and herring.

The finding that a healthy diet was independently related to lower COPD risk appeared to hold up even after accounting for other factors, including smoking history, age, race, exercise habits and being overweight.

Nevertheless, Varraso cautioned against concluding that diet has a direct impact on COPD risk, given that the study participants were medical professionals with a presumably greater focus on health and healthy behavior than the general public. However, the findings underscore the need for more research into how eating patterns affect lung health, Varraso suggested.

"Although COPD prevention efforts should continue to focus on smoking cessation, our results encourage clinicians to consider the potential role of the combined effect of foods in a healthy diet in promoting lung health," said Varraso.

Lona Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas, called the findings "reasonable."

"As always, we need to keep in mind that this type of study suggests potential causes or factors, but does not prove cause," she noted. She also stressed that healthy eaters are also more likely to engage in other healthy behaviors.

"With that said, a healthy diet pattern has been connected with decreasing risk of several other chronic diseases that develop over an extended period of time," said Sandon. "So why should it be any different with COPD?"